This invention relates to closable food containers and more particularly, it concerns food containers in which a container body of substantially rectangular outline and having a generally square opening is adapted to receive by snap fit a cover carrying an initially sealed eating or drinking utensil for consumption of food contained in the receptacle either by penetration or removal of the cover.
U.S. Pat. No. 3,851,411 exemplifies a machine for producing and filling containers in which a drinking straw is packaged with the filled container. In general, the disclosed machine operates to convert three sheets of relatively thin thermoplastic synthethic resinous material into a cube-like receptacle, a cover formed to provide a straw recess, and a removable cover sheet to overlie and at least partially retain a straw until removed and used to consume the liquid drink in the container. The cover and container are permanently sealed to each other and access to the container contents is possible by manually thrusting the straw through a puncturable depression formed in the cover. An example of a container so formed and filled by this type of machine is shown in U.S. Pat. No. 3,874,554.
The packaging system represented by the disclosure of these prior patents is used commercially and has demonstrated substantial promise from the standpoint of providing a low cost, completely sealed and inherently sanitary assembly of a drink container and a straw. The rectangular outline or generally cubic shape of the container is uniquely attractive as well as functional both for conservation of shipping and storage space and for accommodating the packaged straw. In this latter respect, the square configuration of the container top allows a straw of adequate length to be folded in a recess extending diagonally across the cover.
While the existing commercial packaging system is, therefore, highly effective for prepackaged drinks or liquids which may be consumed using a straw, there is need for adaptability of the desirable attributes of the system to a wider range of food products and food or drink marketing procedures. While it is possible, for example, to fill the container with solid or semi-solid food products and substitute a spoon or fork for the straw of the existing container, the permanent seal of the cover to the container prevents or severely impedes the attainment of an opening necessary for the use of a spoon or fork. Also, the present heat sealing or fusion of the cover to the container prevents or at least restricts use of preformed containers and cover/utensil assemblies after manufacture at concession stands or other such food retail outlets where filling is effected at the time of sale.
Although the state-of-the-art relating to closable containers is highly developed and replete with plastic container/cover constructions capable of satisfying the aforementioned needs, several problems are presented in the attainment of a low cost, thermoformed or draw molded rectangular receptacle and an initially sealed but removable cover capable of carrying an enclosed eating or drinking utensil. It is virtually impossible, for example, to attain a good cover-to-container seal along the linear edge of a square opening, given the materials of the existing system, unless one of either the cover edge or the receptacle opening edge envelopes or wraps about the other of such edges. The provision of such a removable edge enveloping sealing closure, however, adds costs particularly to the machinery needed to produce the container and cover.
It is also important that the basic container/cover structure lend itself to production on a given machine and yet be capable of variation to accommodate different marketing requirements. An ideal container for drinks sold at a concession stand, for example, would be one which is easily closed by a cover and straw assembly after filling, easily punctured by the straw and yet difficult or impossible to open in the interest of preventing accidental spillage. The same container used for ice cream or yogurt, on the other hand, whether prefilled by machine or filled after manufacture, and closed by a cover and spoon assembly, must of necessity be easy to open by removing the cover. In addition, the same container used in some marketing circumstances might require a tamper proof adjunct such as a provision for preventing closure of the cover once it is opened. Other marketing circumstances may require emphasis on the space available for advertisement or "billboard space" as it is known in the art. Here again, the basic container structure should be retained in the interest of manufacturing economics.